keys to the vascular plants of east texas - Botanical Research ...

572 CYPERACEAE/CYPERUS
Cyperus flavicomus Michx., (with yellow tuft or crest), WHITE-EDGE FLAT SEDGE. Annual; culms
20–80 cm tall; inflorescences with spikelets in spikes, spread out along an elongate rachis 10–
30 mm long; achenes 0.9–1.2 mm long. Ditches, lake shores; Montgomery (E. Keith, pers. comm.,
SBSC), Jefferson, and Orange (Turner et al. 2003) cos. at se margin of East TX and cited for the
Big Thicket National Preserve by the National Park Service (1995a, 1995b); also n Gulf Prairies
and Marshes and Trans-Pecos. Aug–Oct. Native of the tropics. [C. albomarginatus (Mart. &
Schrad. ex Nees) Steud.] This species has long gone under the name C. albomarginatus (e.g.,
Correll & Johnston 1970; Godfrey & Wooten 1979); however, the epithet flavicomus is older and
thus has nomenclatural priority (Tucker 1985). I
Cyperus floribundus (Kük.) R. Carter & S.D. Jones, (producing abundant flowers). Tufted rhizomatous
perennial; culms 40 cm or less tall; inflorescences with spikelets in a single, loose to
dense spike; longest spikelets 9–21 mm, flexuous-contorted; achenes 1.8–2.4 mm long. Moist
disturbed areas; Travis Co. (Turner et al. 2003) at w margin of East TX; mainly Gulf Prairies and
Marshes and South TX Plains; this species is known only from TX and Mexico. Jun–Sep. [C.
uniflorus Torr. & Hook., not Thunb., C. uniflorus Torr. & Hook. var. floribundus Kük.] This species
has sometimes been synonymized with C. uniflorus or C. retroflexus (e.g., Tucker 1994).
However, we are following Carter and Jones (1997) and Tucker et al. (2002) who argue that this
taxon is worthy of recognition at the specific level.
Cyperus grayoides Mohlenbr., (resembling Cyperus grayi—Mohlenbrock 1959), MOHLENBROCK’S
SEDGE, MIDWESTERN GRAY’S FLAT SEDGE. Tufted perennial from short rhizomatous, tuber-like
base; culms to 35(–50) cm tall; inflorescences with spikelets in loose to dense head-like clusters;
scales of spikelets only slightly overlapping the adjacent scales on the same side of the spikelet
(giving margin of spikelet a distinctive serrate outline); achenes 2–2.4 mm long. Deep sand and
sandy loam in dry, almost barren openings in upland longleaf pine savannahs, mixed pine-oak
forests, and post oak woodlands (Carr 2001), typically on the Willis, Catahoula, Sparta, Queen
City, and Carrizo geologic formations (Bridges & Orzell 1989a); widespread in Pineywoods and
Post Oak Savannah; AR, IL, LA, MO, and TX. May–Nov, depending upon rainfall. The specific
epithet was originally spelled “grayioides’ (Mohlenbrock 1959) but has been corrected to
grayoides (e.g., Kartesz 1999; Tucker et al. 2002). This species is considered to be of conservation
concern by Carr (2001, 2002d) and Tucker et al. (2002), but it apparently is more widespread
than previously thought (e.g., numerous counties cited by Turner et al. 2003). It has been reported
to hybridize with C. retrofractus (Bridges & Orzell 1989a). (RARE 2001, 2002b: G3S3;
Tucker et al. 2002) ?�
Cyperus haspan L., (the native name in Ceylon), SHEATHED FLAT SEDGE, HASPAN FLAT SEDGE.
Tufted perennial; culms (10–)25–70(–100) cm tall, sharply 3-angled; most leaves reduced to
bladeless sheaths or rarely with short blades; spikelets in loose to crowded, digitate, head-like
clusters; achenes 0.5–0.7 mm long. Moist places; widespread in Pineywoods and Post Oak Savannah;
also Gulf Prairies and Marshes, e Edwards Plateau, and Burnet Co. (S.D. Jones, pers. comm.)
near s edge of Cross Timbers and Prairies; se U.S. from VA s to FL w to TX. Jun–Oct. [C. haspan
var. americanus Boeck.] This pantropical to warm temperate species can be a problematic weed
(e.g., in rice fields—Holm et al. 1997). m/284
Cyperus hystricinus Fernald, (porcupine-like, bristly), BRISTLY FLAT SEDGE. Tufted perennial;
culms to 1 m tall, glabrous; rhizomes thick, to 1.5 cm long; leaf blades 4–6 mm wide; inflorescences
with spikelets in oblong spikes that are not wider toward apex, the lower spikelets
markedly reflexed and appearing ± drooping around the peduncle; spikelets golden brown,
with only 1–2(–3) scales; achenes 2.5–2.8 mm long. Xeric sandy soils; scattered in East TX; also
Tarrant Co. (Tucker 1984b) in the Cross Timbers and Prairies and Jim Hogg Co. (Turner et al.
2003) in the South TX Plains; e U.S. from NJ s to FL w to MO and TX. Summer–fall. [C.
retrofractus (L.) Torr. var. hystricinus (Fernald) Kük.]